ARALDITE® CY 220-1 / ARALDITE® CY 221 / HARDENER HY 956

• The flexibility of castings can be adapted to requirements by combining CY 220 -1/ CY 221 in various proportions
• Low tendency to cracking

• The resin component should be stirred and homogenized in the original container before use.
• The casting mix is best prepared by heating the resin up to 40-50°C before stirring in the hardener. Brief degassing of the mix under 5-10 mbar vacuum improves the mixture homogeneity and enhances the dielectric properties of the castings.
• The very low viscosity Araldite CY 221 provides flexible castings, whereas the medium viscosity Araldite CY 220 -1 provides more rigid castings.
• The viscosity of the casting mix and/or the hardness of the castings can be varied by adjusting the mix ratio of the two resins.
• Premixes of the two resins have a shelf life at room temperature of several months.
• To reduce the cure time, the casting is often geled at room temperature and then post cured for 2-6 hours at 60-80°C. Small castings can be processed and directly cured at slightly higher temperatures (40-60°C).
• In case of humid environments (≥75% relative humidity) it is advisable to effect a full cure in an oven at 40-60°C in order to prevent vapor absorption, leading to streaks on the surface of the castings.
• Temperature exothermic rise on curing (e.g. at higher curing temperatures or/and large casting volumines) can be kept within acceptable limits by adding fillers to the mix.

The coloring paste should normally be added to the resin component and mixed with it until homogeneous coloration results. Filled, highly viscous resin components are best heated to 40-60°C to facilitate uniform dispersion of the coloring paste.
Colored resin or mixes of several coloring pastes and resins are stable for some considerable time if stored at room temperature.

The addition of powdered inorganic fillers such as silica flour, microdol, chalk flour, Alumina, aluminum hydroxide etc., has been found to offer considerable advantages in many applications.
Specifically, the use of such fillers:

• enhance important mechanical and electrical properties
• reduce shrinkage and exothermic temperature rise during gelling and cure
•  impart a lower coefficient of thermal expansion
• improve thermal conductivity
• impart a greater elasticity modulus whilst reducing elongation at break

Filled systems
The addition of powdered inorganic fillers such as silica flour, microdol, chalk flour, Alumina, aluminium hydroxide etc., has been found to offer considerable advantages in many applications.

Specifically, the use of such fillers: − 

• enhance important mechanical and electrical properties
• reduce shrinkage and exothermic temperature rise during gelling and cure
• impart a lower coefficient of thermal expansion
• improve thermal conductivity
• impart a greater elasticity modulus whilst reducing elongation at break

We recommend the use of filled encapsulating systems in all applications that requiring high reliability and economical processing.

• The following points should be observed when adding powdered mineral fillers to a casting mix.
• The filler increases the viscosity of the mix. To ensure thorough wetting of the filler, the resin should be heated up to 60-80°C before filler addition.
• When castings have to achieve stringent dielectric requirements the resin/filler mix should be degassed
• The hardener can be added when the resin/filler mix has cooled to room temperature or below 40°C. 

Araldite Colouring Pastes

• The colouring paste should normally be added to the resin component and mixed with it until homogeneous colouration results.
• Filled, highl viscous resin components are best heated to 40-60°C to facilitate uniform dispersion of the colouring paste.
• Coloured resin or mixes of several colouring pastes and resins are stable for some considerable time if stored at room temperature (see instruction sheet, colouring pastes) 

Araldite CY 220-1 
Modified, medium viscosity solvent free epoxy resin

As supplied form - Pale yellow liquid
Hazardous decomposition - Carbon monoxide, carbon dioxide and
products  - other toxic gases and vapours if burned
Disposal - Regular procedures approved by national and/or local authorities 

Araldite CY 221
Modified, low viscosity, solvent free epoxy resin

As supplied form - Clear, liquid
Hazardous decomposition - Carbon monoxide, carbon dioxide and
products - other toxic gases and vapours if burned
Disposal - Regular procedures approved by national and/or local authorities 

Hardener HY 956 EN
Modified, low viscosity hardener based on aliphatic polyamine
 

As supplied form - Clear, light yellow liquid
Hazardous decomposition - Carbon monoxide, carbon dioxide and
products - other toxic gases and vapours if burned
Disposal - Regular procedures approved by national and/or local authorities 

*Large castings should be pre cured at room temperature

Guideline values determined on standard test specimens cured for 6 h/60°C

Contamination of the eyes by resin, hardener or casting mix should be treatedimmediately by flushing with clean, running water for 10 to 15 minutes. A doctor should then be consulted.
Material smeared or splashed on the skinshould be dabbed off, and the contaminated area then washed and treated with a cleansing cream (see above). A doctor should be consulted in the event of severe irritation or burns. Contaminated clothing should be changed immediately.
Anyone taken ill after inhalingvapors should be moved out of doors immediately. In all cases of doubt call for medical assistance.

Store the components in a dry place at 18-25°C, in tightly sealed original containers. Under these conditions, the shelf life will correspond to the expiry date stated on the label. After this date, the product may be processed only after reanalysis. Partly emptied containers should be tightly closed immediately after use.